Rolling mill lubrication

Abstract

Cold rolling metal strip with a rolling lubricant of petroleum solvent mixed with polyalkylene glycol. Where a sump collects said rolling lubricant after use for reuse in such rolling, also using mixtures of such components to lubricate parts of the rolling mill where leakage of the parts lubricants could be collected in the sump.

I claim: 
     
       1. A method of rolling metal in a mill having superimposed work rolls and backup rolls, and having mechanical means controlling operation of said rolls during rolling, comprising applying to the metal passing into the nip of a pair of said work rolls a non-aqueous liquid rolling lubricant consisting of about 0.5 to 25 percent by volume of polyalkylene glycol, the balance being principally petroleum solvent, providing lubricant to said mechanical means substantially entirely consisting of about 5 to 100 percent polyalkylene glycol and about 10 to 95 percent petroleum solvent, collecting the used rolling lubricant in a sump located beneath said rolls, also collecting in said sump at least part of any leakage of said lubricant of said mechanical means during operation of the rolls, admixing the collected roll lubricant with the collected leaked lubricant, and using the admixture as at least part of the rolling lubricant during subsequent rolling in the mill, whereby compatability of the constituents of the rolling lubricant and of the leaked mechanical lubricant is improved for purposes of continued use of the recycled rolling lubricant. 
     
     
       2. The method of claim 1, in which the proportion of polyalkylene glycol in the liquid rolling lubricant applied to the strip is about 1 to 5 percent by volume. 
     
     
       3. The method of claim 2 in which the metal is an alloy containing at least 50 percent by weight of aluminum. 
     
     
       4. The method of claim 1, in which said lubricants applied to the mechanical parts are substantially entirely polyalkylene glycol. 
     
     
       5. The method of claim 1, in which the polyalkylene glycol has a molecular weight in the range of about 1500 to 2500. 
     
     
       6. The method of claim 5, in which the polyalkylene glycol is butoxy polypropylene glycol. 
     
     
       7. The method of claim 1, in which said leaked lubricant includes lubricant leaked form hydraulic roll hold-down means. 
     
     
       8. The method of claim 1, in which said leaked lubricant includes lubricant leaked from bearing means supporting the rolls.